1. Field of Technology
This invention relates to a method for producing copper indium diselenide (CuInSe.sub.2) which can find application in solar cells and other photovoltaic devices such as photosensors. The object of the invention is to provide an improved production process for CuInSe.sub.2 which can be easily carried into practice on a high production basis.
2. Description of the Prior Art
Single-crystal CuInSe.sub.2 has heretofore been produced by weighing Cu, In and Se in stoichiometric proportions into a quartz tube, evacuating the quartz tube to about 10.sup.31 6 mmHg and, after sealing, heating the tube in an electric furnace at a temperature in the range of 1,050 to 1,100.degree. C. to cause a reaction to proceed in the melt phase (for example, P. Migliorato et al., J. Appl. phys., 46 (1975), 1777-1782.) As the contents of the quartz tube are then cooled gradually, CuInSe.sub.2 crystals separate out. CuInSe.sub.2 films have been manufactured by vacuum deposition technology such as vacuum vapor deposition, magnetron sputtering or the like using elementary Cu, In and Se (for example, SERI Photovoltaic Advanced Research & Development, An Overview, SERI/SP-281-2236).
However, the CuInSe.sub.2 produced by the former method, involving a reaction in melt phase, is expensive and, moreover, the manufacturing process itself has the disadvantage that it does not lend itself well to mass production. The latter method, i.e. vacuum deposition technology, has the disadvantage that it does not yield a sufficiently thick film or a film having a sufficiently large area.